<script lang="ts">
import { defineComponent } from 'vue';

import { addClass, removeClass } from '#/utils/domUtils';

export default defineComponent({
  name: 'CollapseTransition',
  setup() {
    return {
      on: {
        beforeEnter(el: any) {
          addClass(el, 'collapse-transition');
          if (!el.dataset) el.dataset = {};

          el.dataset.oldPaddingTop = el.style.paddingTop;
          el.dataset.oldPaddingBottom = el.style.paddingBottom;

          el.style.height = '0';
          el.style.paddingTop = 0;
          el.style.paddingBottom = 0;
        },

        enter(el: any) {
          el.dataset.oldOverflow = el.style.overflow;
          if (el.scrollHeight === 0) {
            el.style.height = '';
            el.style.paddingTop = el.dataset.oldPaddingTop;
            el.style.paddingBottom = el.dataset.oldPaddingBottom;
          } else {
            el.style.height = `${el.scrollHeight}px`;
            el.style.paddingTop = el.dataset.oldPaddingTop;
            el.style.paddingBottom = el.dataset.oldPaddingBottom;
          }

          el.style.overflow = 'hidden';
        },

        afterEnter(el: any) {
          removeClass(el, 'collapse-transition');
          el.style.height = '';
          el.style.overflow = el.dataset.oldOverflow;
        },

        beforeLeave(el: any) {
          if (!el.dataset) el.dataset = {};
          el.dataset.oldPaddingTop = el.style.paddingTop;
          el.dataset.oldPaddingBottom = el.style.paddingBottom;
          el.dataset.oldOverflow = el.style.overflow;

          el.style.height = `${el.scrollHeight}px`;
          el.style.overflow = 'hidden';
        },

        leave(el: any) {
          if (el.scrollHeight !== 0) {
            addClass(el, 'collapse-transition');
            el.style.height = 0;
            el.style.paddingTop = 0;
            el.style.paddingBottom = 0;
          }
        },

        afterLeave(el: any) {
          removeClass(el, 'collapse-transition');
          el.style.height = '';
          el.style.overflow = el.dataset.oldOverflow;
          el.style.paddingTop = el.dataset.oldPaddingTop;
          el.style.paddingBottom = el.dataset.oldPaddingBottom;
        },
      },
    };
  },
});
</script>
<template>
  <transition mode="out-in" v-on="on">
    <slot></slot>
  </transition>
</template>
